3D Electro-thermal modelling of bonding and metallization ageing effects for reliability improvement of power MOSFETs

► We investigate failures of vertical power MOSFET due to metallization ageing. ► Temperature and On-resistance decrease with the increase of the bonding wire gauge. ► Also, they decrease with the increase of contact area with top metallization. ► Hot spot and thermal runaway appear earlier in case of aged device. ► The mould compound has a poor influence on device cooling is poor. This paper presents a methodology, based on 3D electro-thermal simulation, to investigate failures of vertical power MOSFET due to metallization ageing of source terminal. Modelling steps to obtain a 3D finite element modelling of MOSFET are presented with the smart approximations and limitations of MOSFET electrical behaviour. The effects of bonding wire gauge and contact area with top metallization are studied to optimize the power device design. The power device thermal runaway phenomenon and hot spot formation has been simulated and discussed.